Trends in the use of partial nephrectomy for cT1 renal tumors: analysis of a 10-yr european multicenter dataset
Although several studies from US cancer registries have reported the underuse of PN for cT1 renal tumors, at the best of our knowledge, this trend in European centres has not been addressed. In this study we evaluated the impact of hospital volume on the trend in performing PN vs. radical nephrectomy (RN) for cT1 renal tumors.
Materials and Methods
A retrospective analysis of data collected at 10 European centres was performed to evaluate the trends in the use of PN in the last decade among centers with different “kidney cancer” yearly caseload.
Centers were considered as “low volume”, “mid volume” or “high volume” when the mean yearly caseload was <15, 15-35, and >35 cases/year, respectively.
The trend in the use of PN (rate of PN/total procedures) for cT1 renal tumors was evaluated with the average annual percent change (AAPC) for each group. This test provides a measure of the weighted average of the slope over a fixed time interval. The trends were then compared one versus each other with the joinpoint regression analysis (Joinpoint software version 220.127.116.11).
Overall, 2526 patients were treated: 1505 (59.6%) were treated at 2 high volume centers, 887 (35.1%) at 5 mid volume centers and 134 (5.3%) at 3 low volume centers.
The trend in the surgical treatment of cT1 renal tumors in low-volume centers confirmed the underuse of PN in the last decade; besides, the trend did not show any significant improvement along the decade, neither for cT1,nor for cT1a, nor for cT1b (p=0.67, p=0.7, p=0.76, respectively).
On the contrary, in mid volume centres there was a significant paradigm shift in favor to PN, both for cT1, and for cT1a and for cT1b renal tumors (p=0.002, 0.0005 and 0.007, respectively).
High volume centres experienced the strongest paradigm shift toward PN (all p<0.0001).
The trends for cT1, cT1a and cT1b renal tumors were depicted in Figure 1,2 and 3, respectively.
A between group comparison confirmed the trends both for high volume and for mid volume significantly different by that of low volume centres (all p ≤0.002) and highlighted statistically significant different also between mid volume and high volume centres (all p ≤0.03). Results of joinpoint regression analysis, with AAPC values, 95% CI, slope p values and between group comparisons were summarized in table 1.
Partial nephectomy is today an established treatment for cT1 renal tumors. Both the European Association of Urology and the American Urological Association guidelines recommend partial nephrectomy as the treatment of choice for cT1 renal tumors when "technically feasible". [1,2]
The feasibility of such treatment is mainly driven by surgical skills, therefore the trend toward a wide use of partial nephrectomy is based on a minimum caseload that guarantees the sufficient surgical skill.
While some Authors have reported an increasing trend in performing partial nephrectomy in US institutions along the last decade, at the best of our knowledge, this is the first report on the trend in the use of partial nephrectomy versus radical nephrectomy in European centres.
The use of partial nephrectomy as treatment of choice for cT1 renal tumors is mainly based on surgical skills.
These data, obtained by a large multi-institutional dataset, confirm the strong role of yearly caseload in determining the paradigm shift toward partial nephrectomy for cT1 renal tumors. Based on these findings, the paradigm shift observed in mid volume centres along this decade suggests that the achievement of a minimum caseload would turn the tide also in low volume centres.
Finally, the significant difference observed between high volume and mid volume centres confirm the importance of a selective referral to high volume centres, especially for cT1b renal tumors.